Stimulation method and apparatus for attempting to return a physiological parameter of a patient to normal

ABSTRACT

A selected physiological parameter of a patient, such as the respiration or heart beat of the patient, is monitored. When certain variations in the monitored parameter are detected, a stream of pressurized fluid, such as air, is directed against the patient&#39;&#39;s body to provide cutaneous stimulation in an effort to return the monitored parameter to normal.

United States Patent 91 1 3,730,173 Deaton 1 1 May 1, 1973 15 1 STIMULATION METHOD AND 2,178,986 1'17'1'6'3'9" csiawai...i....;.; .;....;.;.'..s46/d6'1- APPARATUS FOR ATTEMPTING TO RETURN A PHYSIOLOGICAL PARAMETER OF A PATIENT TO NORMAL David W. Deaton, Dallas, Tex,

Assignee: Ahldea Corporation, Dallas, Tex.

Filed: Feb. 2, 1970 Appl. No.: 7,792

Inventor:

References Cited UNITED STATES PATENTS 8/1904 Crosby et a1. ..340/279 2,199,060 4/1940 Young ....340/279 2,625,594 1/ 1953 Mathis ..340/279 3,032,029 5/1962 Cunningham.. .....128/2.1 B 3,144,019 8/1964 Haber ..128/2.06 B 3,493,703 2/ 1970 Finan ....340/279 UX 3,547,106 12/1970 Bornmann ..128/2 R 3,588,864 6/1971 Gaulke ....340/279 3,163,161 12/1964 Courtin ..l28/38 Primary Examiner-William E. Kamm Attorney-Richards, Harris & Hubbard [5 7] ABSTRACT A selected physiological parameter of a patient, such as the respiration or heart beat of the patient, is monitored. When certain variations in the monitored parameter are detected, a stream of pressurized fluid, such as air, is directed against the patients body to provide cutaneous stimulation in an effort to return the monitored parameter to normal.

8 Claims, 4 Drawing Figures 78 MONITORING DEVICE 74 VOLTAGE CONTROLLED OSCILLATOR VOLTAGE 1/52 6/ SOURCE 70 50 vAsiBkgEDC 8 T SOURCE LIGHT/ BUZZER, 30

a0 26 COMPRESSED AIR AiR v TO SOURCE PATIENT Patented May 1, 1973 VOLTAGE CONTROLLED A LIGHT/ BUZZER AIR TO PATIENT OSCILLATOR VARIABLE 0c VOLTAGE SOURCE 56 MONITORING DEVICE YVOLTAG'E SOURCE FIG. 2

INVENTOR:

N m. m W m V M ATTORN EY STIMULATION METHOD AND APPARATUS FOR ATTEMPTING TO RETURN A PHYSIOLOGICAL PARAMETER OF A PATIENT TO NORMAL FIELD OF THE INVENTION This invention relates to patient monitoring and stimulation, and more particularly to the monitoring of physiological parameters of a patient and cutaneous stimulation of the patient in response to parameter variation.

THE PRIOR ART It is important to carefully monitor certain physical characteristics or physiological parameters of certain hospital patients. For example, small premature infants are often subject to transient cessation of respiration, termed apnea. Additionally, the condition of patients having heart conditions must be monitored carefully to detect variations in the heart rate. A number of different types of monitoring techniques have been heretofore developed to monitor these and other physiological parameters, as for example, impedance pneumography commonly used to monitor respiratory changes.

Many such prior monitoring devices have relied upon a visual or audible alarm which is actuated upon the detection of the physiological parameter variations,

SUMMARY OF THE INVENTION In accordance with the present invention,a system is described which automatically provides cutaneous stimulation to a patient upon the occurrence of a prescribed variation in a monitored physiological parameter.

In accordance with a more specific aspect of the present invention, structure is provided to monitor a physical characteristic of a patient. A device responsive to a variation in the physical characteristic is operative to direct a stream of pressurized fluid against a portion of the patients body to provide cutaneous stimulation thereto.

In accordance with another aspect of the invention, a conduit is provided between a source of pressurized fluid such as gas and the body of a patient. Circuitry is provided to control the admission of the pressurized fluid through the conduit to provide cutaneous stimulation to the patient when desired. In the preferred embodiment, a stream of pressurized gas is directed against the patients body when the respiration or heartbeat of the patient varies beyond predetermined limits.

DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention and for further objects and advantages thereof, reference may now be made to the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a somewhat diagrammatic illustration of the connection of the present stimulator system to a patient;

FIG. 2 is a block diagram of the preferred embodiment of the present stimulator system;

FIG. 3 is a view of a body attachment member for use with the invention; and

FIG. 4 is a side view of the body attachment member shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT comprise a small premature infant known to be subject to apnea, along with associated heart rate changes. A pair of electrodes 12a-b are attached to the patients chest, preferably in the mid axillary line at a suitable level above the diaphragm. To insure adequate contact at the electrode site, adhesive discs and hypertonic electrode gel may be disposed on the electrodes. Wires l4a-b connect the electrodes to a case 16 which contains a conventional impedance pneumograph.

As is well known, such pneumograph systems measure the change of impedance of the patients chest caused by the respiration of the patient. If desired, indications may also be provided by the electrodes 12a-b of the heart rate of the patient 10 and applied to circuitry within the casing 16. While it will be understood that a variety of suitable systems are commercially available for monitoring the respiration and heart rate of a patient, a suitable respiration and heart monitoring system for use with the present invention is the system sold under the tradename Infalarm, manufactured and sold by IMI, Division of Becton, Dickinson and Company. Such a system provides visual indications of the respiration rate at an indicator dial l8 and a visual indication of the heart rate atan indicator dial 20. Suitable control knobs 22 are provided to allow adjustment of the sensitivity and operation of the monitoring device.

In the preferred embodiment of the invention, the physical characteristic or physiological parameter of the patient 10 which is monitored is the respiration rate and/or the heart rate of the patient. However, it willbe understood that other physiological parameters or physical conditions such as EEG or conditions of the central nervous system of the patient could be likewise monitored in the operation of the invention. If desired, the amount of movement of the limbs of a patient may be measured, with a signal being generated if a sufficient amount of movement does not occur over a like. Other monitoring devices comprise mechanical linkages attached to a bellows or the like into which the patient breathes. The position of the mechanical linkage is then monitored and an alarm device is triggered by unusual movement of the mechanical linkages. Other monitoring devices of physiological parameters or physical conditions of patients are likewise encompassed within the scope of the invention.

Additionally contained within the casing 16 is a system which generates an electrical control signal via lead 24 when the monitored physiological parameter varies beyond a preset threshold or range. This electrical signal operates a conventional solenoid valve 26 positioned in a fluid conduit 28. The conduit 28 extends between a source 30 of compressed fluid, such as air, and an attachment member 32 which is affixed to a portion of the patients body. In the embodiment illustrated in FIG. 1, the attachment member 32 is taped or otherwise suitably affixed to the patient's foot. When the monitoring device senses a dangerous variation in the heart rate, respiration rate or other physiological parameteror the patient, an electrical signal is applied via lead 24 to open valve 26 to allow the passage of high pressure fluid through the conduit 28 to the sensitive area of the patients foot.

The force of the pressurized fluid impinging against the surface of the patient's body has been found to provide sufficient cutaneous stimulation in order to return the patients respiration or heart rate to normal in the large majority of instances. Particularly advantageous is the fact that the cutaneous stimulation provided by the system is automatic and may be applied quickly within a prescribed time in order to prevent the variation of the physiological parameter from becoming acute.

The conduit 28 preferably comprises a flexible tube made from plastic or the like of a sufficient diameter to allow substantial flow of air or gas therethrough. It has beenfound in use that a source of oxygen or other suitable gas with a pressure of 50p.s.i. provides satisfactory cutaneous stimulation for infant patients. It will be understood that while the attachment member 32 is illustrated as being placed on the infant's foot, that the member may alternatively be placed on other portions of the patients body, such as the stomach area.

A knob 34 is presented on the front panel of the casing 16 to enable adjustment of the sensitivity of the system. As will be later described, a knob 36 is provided to enable adjustment of the frequency of pulsing of the valve 26 when a pulsing operation is desired. A knob 38 is provided to enable adjustment of the time delay which occurs after the initial sensing of the parameter variation and the time at which the valve 26 is opened. A switch 40 controls the on/off operation of the system. A knob switch 42 enables the valve 26 to be continuously opened to provide a continuous flow of air against the patient's body, if desired. A pushbutton switch 44 may be manually operated to operate the valve 26 when desired in a continuous manner, or in a selective manual intermittent manner. A switch knob 46 enables the selective operation of the system without the requirement of a monitoring signal. While the present system has been shown as being enclosed in casing 16, along with a suitable apnea monitor system, it will be understood that the present stimulator system may be packaged in a separate package and connected to a conventional apnea monitor.

Referring to FIG. 2, wherein like andcorresponding numbers are used for previously identified parts, a block diagram of the present system is illustrated. A suitable voltage source 50 is connected via a two-position switch 40 to a step-down transformer 52. Voltage source 50 will conventionally comprise a 1 10 AC source, with the secondary of the transformer 52 providing a lower voltage for use in the system. The output of the transformer 52 is applied to a conventional relay circuit 54. A physiological parameter monitoring device 56 supplies an output signal via an amplifier 58 to the relay 54. In the preferred embodiment, the monitoring device 56, which may comprise any suitable device for monitoring the selected physiologi cal parameter of the patient, such as the apnea monitor heretofore described, supplies an electrical signal via amplifier 58 to the relay 54 as long as the patient is breathing properly. The relay switch arm 60 is thus normally held in the illustrated position so that no stimulation is provided to the patient.

When the patients breathing stops or varies beyond a predetermined threshold, the electrical signal applied to the relay 54 is terminated or is reduced below the energizing level of the relay 54. The relay 54 is thus deenergized and the relay switch arm 60 moves to connect to terminal 62. The AC voltage signal is then connected from source 50 to a delay circuit comprising a resistor 64 and a variable capacitor 66 connected to circuit ground. The capacitor 66 may be varied by the control knob 38 mounted on the panel in order to vary the delay characteristics of the delay circuit. Alternatively, the resistor 64 may be'varied by knob 38. A relay 70 is connected to one terminal of the capacitor 66, such that when the voltage built up across capacitor 66 is sufficient, the relay 70 is energized. The relay switch arm 72 is then closed upon contact 74.

The output of a variable DC voltage source 76 is connected to the relay switch arm 72. The knob 36 can be rotated to adjust a potentiometer or the like to vary the amount of DC voltage applied from the source 76. The DC voltage is applied to a voltage controlled oscillator circuit 78, which generates an output AC voltage having a frequency dependent upon the magnitude of DC voltage applied thereto. This frequency controlled signal is then applied to the valve 26 connected in the conduit 28. Valve 26 will normally comprise a conventional solenoid actuated valve capable of operating with air pressures over 50p.s.i. A regulator 80 may be disposed in the conduit 28 on the output of the compressed air source 30, in order to enable selective adjustment of the pressure of the air applied to the patient through the valve 26.

A normally open switch 46 is connected between the output of the secondary of transformer 52 and the terminal 62 in order to enable selective bypassing of the monitoring control provided by the device 56. A normally open switch 42 is connected between the secondary of the transformer 52 and the valve 26 in order to supply a continuous, single frequency pulsating energizing signal to the valve 26. Pushbutton 44 may be selectively operated to also provide a continuous pulsating actuating signal to the valve 26. A-switch 81 is connected to the output of the DC voltage source 76 and the valve 26 in order to provide a DC energizing signal to the valve 26 to maintain the valve in a continuously open position when desired. A light or buzzer alarm system 82 is connected to the output of the voltage controlled oscillator 78in order to enable an alarm to be actuated when the present stimulator system is operated.

In the operation of the system shown in FIG. 2, as long as a suitable output signal is provided from the monitoring device 58, the relay 54 maintains the relay arm 60 in the illustrated position. When the monitored physiological parameter of the patient varies, the relay 54 is de-energized and the relay switch arm 70 connects to the terminal 62. An AC voltage is then applied to the delay circuit when the switch 40 is closed. The delay circuit comprises the resistor 64 and the capacitor 66, or any other suitable electrical delay device. By adjustment of a knob 38, the desirable delay for the system is set, with a practical range of delays being between 0 and 40 seconds.

After the desired delay, a sufficient voltage is applied to the relay 70 to close the relay switch arm 72 upon the terminal 74. This supplies a direct current voltage from the source 76 to the voltage controlled oscillator 78. The magnitude of the voltage provided by source 76 may be adjusted by rotation of the knob 36. The oscillator 78 generates an AC signal having a frequency dependent upon a magnitude of the'DC voltage applied from source 76. Oscillator 78 may comprise any conventional VCO, or other equivalent circuit. The output of the oscillator 78 is applied to the valve 26 in order to periodically provide a pulsating supply of pressurized gas to the patient to provide cutaneous stimulation thereto. Additionally, the light or buzzer system 82 is energized. If desired, the switch 81 may be thrown and the valve 26 is maintained in an open position to allow selective application of continuous pressurized air to the patient when desired. Additionally, selective operation of the switches 42, 44 or 46 enable various alternative manual operations of the stimulator when desired.

FIGS. 3 and 4 illustrate an embodiment of a suitable attachment member for attaching the conduit 28 to the patients body. The device comprises a circular rubber member 90 having a central aperture 92 therein and including an extending cylinder portion 94 on the rear side thereof. Conduit 28 is of a diameter to fit within the cylinder member 94. A snap-in flexible clamp member 96 is inserted in the end of conduit 28. A clamping band 98 provides a sufficient pressure to the cylinder 94 and the clamping member 96 to maintain the end of the conduit 28 firmly attached. The circular member 90 may be attached to the body of the patient by an adhesive substance or by tape. Apertures may be provided in the circular member '90 to allow the escape of the pressurized air in some instances.

Whereas the present invention has been described with respect to specific embodiments thereof, it will be understood that various changes and modifications will be suggested to one skilled in the art, and it is intended to encompass such changes and modifications as fall within the scope of the appended claims.

What is claimed is:

1. A method of cutaneous stimulation comprising:

monitoring a physiological parameter of a patient generating a stream 0 flui in. response to varia ion of the physiological parameter past a predetermined threshold value,

directing said stream of fluid through a conduit against a localized area of the skin of the patient in an effort to return the physiological parameter to within said threshold value and varying said stream of fluid during direction against the skin of the patient according to a predetermined program.

2. The method of claim 1 wherein said stream of fluid comprises a stream of high pressure gas.

3. The method of claim 1 wherein the physiological parameter comprises:

the respiration of the patient.

4. The method of claim 1 wherein the physiological parameter comprises:

theheart beat of the patient.

5 A system for stimulation of the body of a patient comprising:

a source of pressurized fluid,

a conduit extending from said source, the means for attaching one end of said conduit in the region of a sensitive portion of the body of the patient,

valve means connected to control the passage. of

fluid through said conduit,

means for detecting a physiological parameter of the patient, and

electrical circuit means responsive to said detecting means for operating said valve means to control the admission of fluid through said conduit to provide cutaneous stimulation of the patient in an effort to return the physiological parameter to normal.

6. The system of claim 5 wherein said detecting means comprises means to detect the respiration of the patient.

7. The system of claim 5 wherein said detecting means comprises means to detect the heart beat of the patient.

8. The system of claim 5 wherein said detecting means comprises means to detect variations in a selected physiological parameter of the patient. 

1. A method of cutaneous stimulation comprising: monitoring a physiological parameter of a patient, generating a stream of fluid in response to variation of the physiological parameter past a predetermined threshold value, directing said stream of fluid through a conduit against a localized area of the skin of the patient in an effort to return the physiological parameter to within said threshold value and varying said stream of fluid during direction against the skin of the patient according to a predetermined program.
 2. The method of claim 1 wherein said stream of fluid comprises a stream of high pressure gas.
 3. The method of claim 1 wherein the physiological parameter comprises: the respiration of the patient.
 4. The method of claim 1 wherein the physiological parameter comprises: the heart beat of the patient.
 5. A system for stimulation of the body of a patient comprising: a source of pressurized fluid, a conduit extending from said source, the means for attaching one end of said conduit in the region of a sensitive portion of the body of the patient, valve means connected to control the passage of fluid through said conduit, means for detecting a physiological parameter of the patient, and electrical circuit means responsive to said detecting means for operating said valve means to control the admission of fluid through said conduit to provide cutaneous stimulation of the patient in an effort to return the physiological parameter to normal.
 6. The system of claim 5 wherein said detecting means comprises means to detect the respiration of the patient.
 7. The system of claim 5 wherein said detecting means comprises means to detect the heart beat of the patient.
 8. The system of claim 5 wherein said detecting means comprises means to detect variations in a selected physiological parameter of the patient. 